The present invention relates to a broadband corrugated horn radiator including a hybrid mode exciting member whose inner cross section is constant over its entire length and a transition member from the cross section of the hybrid mode exciting member to the cross section of the horn aperture.
Corrugated horn radiators are used as primary radiators in reflector antennas. Such radiators are distinguished by a low cross-polarization level, freedom from reflections, good sidelobe suppression and a rotationally symmetrical radiation lobe (E-H matching of the lobe cross sections). A corrugated horn radiator should have these good properties over the broadest possible frequency range. It has, in the past, been attempted, for example in German Auslegeschrift No. 2,152,817, to enlarge the bandwidth by changing the frequency dependency of the impedance at the inner walls of the horn radiator. This is accomplished, according to German Auslegeschrift No. 2,152,817, by special design and dimensioning of the corrugated groove structure in the hybrid mode excitation member and in the transition member to the horn aperture which follows.
However, the transmission bandwidth of the horn radiator cannot be enlarged very much merely by modifying the impedance curve within such a horn radiator.